<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h1>null与undefined</h1>


<script>
    let obj1 = null;
    let obj2 = undefined;
    console.log(obj1==obj2);
    console.log(obj1===obj2);
    console.info(Number(obj1)); // 0
    console.info(Number(obj2)); // NaN
    console.info(5 + obj1);// 5
    console.info(5 + obj2)// NaN
</script>
</body>
</html>